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Overview

The system runs the /usr/local/cpanel/bin/checkallsslcerts script during the nightly cPanel & WHM update (upcp) process. This script performs the following actions:

  • Installs a cPanel-signed hostname certificate on the server, if one does not exist.
  • Updates the SSL certificate for all cPanel & WHM services.
  • Issues a Sectigo®-signed SSL certificate on any server with a self-signed, expired, or soon-to-expire certificate.

Warning:

We strongly recommend that you only manually run this script if cPanel Technical Support advises you to do so.


Note:

In the past, cPanel & WHM services used a self-signed certificate. Now all cPanel & WHM services use a cPanel-signed hostname certificate with a Sectigo trust chain. This document explains how the system installs a cPanel-signed hostname certificate and how to disable the automatic installation of a cPanel-signed hostname SSL certificate if you do not wish to use it.


The /usr/local/cpanel/bin/checkallsslcerts script

When the /usr/local/cpanel/bin/checkallsslcerts script runs, the system performs the following steps:

Reminder:

We strongly recommend that you only manually run this script if cPanel Technical Support advises you to do so.

  1. The system creates a Domain Control Validation (DCV) file, which resembles the following example:

    4221C402112E4831C72C2E004614C47C.txt

    Notes:

    • Systems that use EasyApache 3 store this file in the /usr/local/apache/htdocs/.well-known/pki-validation/ directory.
    • Systems that use EasyApache 4 store this file in the /var/www/html/.well-known/pki-validation directory.
  2. The system performs a DNS lookup for the hostname's IP address on the root nameservers. To do this, it runs the following command:

    dig =trace hostname.example.com

    Notes:

    • If the dig command returns multiple IP addresses, the system uses the first IP address that the command returns.
    • In this example, hostname.example.com represents the server's hostname.
  3. The system uses the hostname's IP address to confirm that it can access the Domain Control Validation (DCV) file. To do this, it runs the following command:

    curl 192.0.2.0/AFAA5C66A1EEF5812703A46C21C013B4.txt

    Note:

    In this example, 192.0.2.0 represents the primary IP address, and AFAA5C66A1EEF5812703A46C21C013B4.txt represents the DCV file.

  4. When the local DCV check passes, the system sends a request to the cPanel Store API for the new SSL certificate.

    • If a valid SSL certificate exists and matches the DCV file, the system does not perform any action.

    • If the system must issue a new SSL certificate, the system sends a request to Sectigo.
    • Sectigo validates the DCV file from the following IP addresses: 

      Important:

      Sectigo uses these IP addresses to attempt to access the cPanel server. You must whitelist these IPs in the server firewall. For more information, read our How to Configure Your Firewall for cPanel Services documentation.

      178.255.81.12
      178.255.81.13
      91.199.212.132
      199.66.201.132
  5. The system logs the Sectigo requests in the /etc/apache2/logs/access file. It also contains user agent strings that show who accesses the DCV file. These user agent strings resemble the following examples:

    192.0.2.0 - - [16/Jun/2016:16:16:16 -0500]  "GET /4221C402112E4831C72C2E004614C47C.txt HTTP/1.1" 200 53  "-" "Cpanel-HTTP-Client/1.0"
    192.0.2.0 - - [16/Jun/2016:16:16:16 -0500]  "GET /4221C402112E4831C72C2E004614C47C.txt HTTP/1.1" 200 53  "-" "Cpanel-HTTP-Client/1.0"
    199.66.201.132 - - [16/Jun/2016:16:18:46 +0000]  "GET /4F571E4CB76F46E37B8118CEA1DB42BA.txt HTTP/1.1" 200 53  "-" "SECTIGO DCV"
    199.66.201.132 - - [16/May/2016:16:18:46 +0000]  "GET /4F571E4CB76F46E37B8118CEA1DB42BA.txt HTTP/1.1" 200 53  "-" "SECTIGO DCV"

Arguments

The /usr/local/cpanel/bin/checkallsslcerts script includes the following arguments:

ArgumentsDescription
--verbose

Adjusts output to include messages that resemble the following:

  • The system will attempt to replace the self-signed certificate for the “cpanel” service with a signed certificate from the cPanel Store.
  • The system will attempt to replace the self-signed certificate for the “dovecot” service with a signed certificate from the cPanel Store.
  • The system will attempt to replace the self-signed certificate for the “exim” service with a signed certificate from the cPanel Store.
  • The system will attempt to replace the self-signed certificate for the “ftp” service with a signed certificate from the cPanel Store.
--allow-retry

If the cPanel Store continues the hostname certificate request, then the system checks the cPanel Store again in an hour. To do this, it runs the following command:

/usr/local/cpanel/scripts/try-later --action '/usr/local/cpanel/bin/checkallsslcerts --no-retry' --check '/bin/sh -c exit 1' –delay 60 --max-retries 1 --skip-first

If the system must retry the SSL certificate update process, an entry will appear in the at daemon ( atd ) job queue.

To view, execute, or remove a job, the /usr/local/cpanel/scripts/try-later command runs with one of the following arguments:

ArgumentDescription
atq Views queue at jobs.
at -c #
Views contents of a specific job number.
at -c # | sh Manually executes a job.
atrm # Manually removes a job.

Output

If this script detects errors when it runs, it sends an email to the system administrator that contains warnings about those errors.  

Disable a cPanel-signed hostname certificate

To disable a cPanel-signed hostname certificate's installation, run the following command:

touch /var/cpanel/ssl/disable_auto_hostname_certificate

To disable the automatic replacement of all expired service certificates and disable notifications about expired or expiring service certificates, run the following command:

touch /var/cpanel/ssl/disable_service_certificate_management


Additional documentation